1. Field of the Invention
The present invention relates to flexible membrane dam which is disposed at the bottom of a body of water and is used as a weir, a wave-breaking dyke, or the like, and to a mounting member used for fixing the flexible membrane dam. In particular, the present invention relates to a flexible membrane dam which, due to the inflation and contraction of the flexible membrane, i.e., due to the flexible membrane dam being erected and collapsed, can effectively prevent or control the flow of water, the propagation of waves, or the like, and at which concentration of stress when the dam is erected can be prevented, and to a mounting member for this flexible membrane dam.
2. Description of the Related Art
The flexible membrane which forms the main body of a flexible membrane dam is formed as a flat, elongated sheet by integrally vulcanization molding a reinforcing core body layer such as ordinary canvas or the like with an elastic body such as rubber or the like.
Such a flexible membrane is three-dimensionally mounted to a foundation having a river bottom surface portion of the foundation, which is substantially horizontal at the bottom of a river and corresponds to the bottom of a river, and an inclined surfaces portion of the foundation, which correspond to slanted surfaces such as river banks or dykes or the like. The flexible membrane inflates into a three-dimensional configuration having curved surfaces in three dimensions.
In order to mount the flat, elongated flexible membrane along the widthwise direction of a river three-dimensionally as described above, it is necessary to use a special means therefor.
One example of a flexible membrane dam is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 10-96225.
In this flexible membrane dam, step-like portions are formed in the inclined surfaces portion for easing the concentration of stress which occurs when the flexible membrane is standing. The outer peripheral edge portion of the flexible membrane is mounted to these step-like portions.
However, providing such step-like portions in the inclined surfaces portion makes installation complex and requires much work.
Further, by providing the step-like portions in the inclined surfaces portion, the concentration of stress at the time the flexible membrane is standing is alleviated to a certain extent, but an even greater suppression of such concentration of stress is desired.
In view of the aforementioned, an object of the present invention is to provide a flexible membrane dam and a mounting member in which installation is easy, and a concentration of stress at the time a flexible membrane is standing can be alleviated even more than in the conventional art.
A first aspect of the present invention is a mounting member used in a flexible membrane dam which is formed by a flexible expanding-and-contracting structural body which is formed from a flexible membrane and is made to stand by a fluid being supplied to an interior thereof and made to collapse by fluid being discharged from the interior thereof; and a structure at which the flexible expanding-and-contracting structural body is provided, the mounting member comprising: a first member and a second member, wherein the first member is provided at the structure and abuts one surface of the flexible membrane, the second member abuts another surface of the flexible membrane, a vicinity of an outer peripheral edge of the flexible membrane is nipped by a fixing means between the first member and the second member, at a surface of the first member which abuts the flexible membrane, first concave portions and first convex portions, which extend in a direction orthogonal to the outer peripheral edge of the flexible membrane, are provided alternately along the outer peripheral edge of the flexible membrane, at a surface of the second member which abuts the flexible membrane, second convex portions which oppose the first concave portions and second concave portions which oppose the first convex portions are provided alternately along the outer peripheral edge of the flexible membrane, and a length L1 of the flexible membrane, in a state in which the flexible membrane is set in close contact with bottom surface of the second concave portion, from a flexible membrane outer peripheral edge side end portion of the second concave portion to an end portion of the second concave portion at a side opposite the flexible membrane outer peripheral edge side of the second concave portion, and a length L2 of the flexible membrane, in a state in which the flexible membrane is set in close contact with peak surface of the second convex portion, from a flexible membrane outer peripheral edge side end portion of the second convex portion to an end portion of the second convex portion at a side opposite the flexible membrane outer peripheral edge side of the second convex portion, are substantially equal.
In the first aspect, the mounting member is provided at the structure at which the flexible expanding-and-contracting structural body is provided ,at the flexible membrane dam which is set in a river or the like. More specifically, the mounting member is provided at the inclined surface portion of the structure (the mounting base).
The flexible membrane is nipped between the first member and the second member and is fixed by a fixing means (e.g., anchor bolts provided at the structure, and nuts screwed therewith, or the like).
A vicinity of the outer peripheral edge of the flexible membrane is nipped and fixed between the first member and the second member. In this way, the vicinity of the outer peripheral edge of the flexible membrane is curved in a convex and concave shape along the direction of the outer peripheral edge.
When a fluid such as air is supplied to the interior of the flexible expanding-and-contracting structural body formed from the flexible membrane so that the flexible expanding-and-contracting structural body inflates and stands, the portions of the flexible membrane at the side opposite the outer peripheral edge side stand substantially orthogonally with respect to the inclined surfaces portion. Further, due to these portions being pulled in the substantially orthogonal direction with respect to the outer peripheral edge, the flexible membrane is fit closely to the bottom surfaces of the concave portions and the peak surfaces of the convex portions of the second member.
Here, because L1 (for the second concave portion) and L2 (for the second convex portion) are set to be substantially equal, the formation of convex and concave portions in the standing portions of the flexible membrane is prevented. At the inflated flexible expanding-and-contracting structural body, stress is applied uniformly in the direction of the outer peripheral edge of the flexible membrane. Accordingly, there is no concentration of stress caused by the formation of convex and concave portions in the flexible membrane, and thus, the durability of the flexible membrane improves.
In second aspect of the present invention, in the mounting member of the first aspect, (L1/L2)xc3x97100 is substantially in a range of 80 to 120.
L1 is a length of the flexible membrane, in a state in which the at flexible membrane is set in close contact with bottom surface of the second concave portion, from a flexible membrane outer peripheral edge side end portion of the second concave portion to an end portion of the second concave portion at a side opposite the flexible membrane outer peripheral edge side of the second concave portion. L2 is a length of the flexible membrane, in a state in which the flexible membrane is set in close contact with peak surface of the second convex portion, from a flexible membrane outer peripheral edge side end portion of the second convex portion to an end portion of the second convex portion at a side opposite the flexible membrane outer peripheral edge side of the second convex portion. The ratio of L1 to L2, i.e., (L1/L2)xc3x97100, falls in the range of 80 to 120. Namely, the length L2 is close to the length L1. Thus, in the flexible expanding-and-contracting structural body which is inflated, stress is applied uniformly in the direction of the outer peripheral edge of the flexible membrane.
If (L1/L2)xc3x97100 falls out of the range of 80 to 120, when the flexible expanding-and-contracting structural body inflates, there will be a local concentration of stress at the flexible membrane in a vicinity of the second member, which is not preferable.
It is preferable that (L1/L2)xc3x97100 is 85 to 115, and more preferable that (L1/L2)xc3x97100 is 95 to 105.
In the mounting member of the first or the second aspect, a plurality of ribs extending along the outer peripheral edge of the flexible membrane are provided at the surface of the second member which abuts the flexible membrane, and a number of ribs provided at the second convex portion is smaller than a number of ribs provided at the second concave portion.
Ribs, which extend along the outer peripheral edge of the flexible membrane, are formed at the surface of the second member which opposes the first member. In this way, the friction generated between the second member and the flexible membrane increases, and slipping at the time a large tensile force is applied to the flexible membrane can be prevented.
The number of ribs of the second convex portions is less than the number of ribs of the second concave portions. Thus, the length L2 is made to be closer to the length L1 by an amount corresponding to this number of ribs which are the difference between the number of ribs of the second convex portions and the number of ribs of the second concave portions.
In a fourth aspect of the present invention, in any of the first through third aspects, an end portion of the second member at a side opposite a flexible membrane outer peripheral edge side of the second member includes a chamfer.
The end portion of the second member at the side opposite the flexible membrane outer peripheral edge side is a portion which abuts the flexible membrane and bendingly deforms the flexible membrane. If this end portion is sharp, the flexible membrane will bend abruptly, and the durability thereof will deteriorate. Accordingly, by subjecting this end portion to chamfering processing, the durability of the flexible membrane improves.
In a fifth aspect of the present invention, in the mounting member of the fourth aspect, the chamfer has a radius of curvature.
By subjecting the end portion of the second member at the side opposite the flexible membrane outer peripheral edge side to R chamfering processing, the flexible membrane curves gradually, and thus, the durability thereof is improved even more.
In a sixth aspect of the present invention, in the mounting member of the fifth aspect, the flexible membrane has a thickness T, and a radius of curvature at the second convex portion is R, R greater than 2.5T.
The thickness of the flexible membrane is T, and the R chamfering processed radius of curvature at the second convex portion is R. If R greater than 2.5T, the portion abutting the flexible membrane will be a smooth circular arc.
If Rxe2x89xa62.5T, the R chamfering processed radius of curvature will be small with respect to the thickness of the flexible membrane, and the end portion will resemble a sharp configuration which is not preferable.
It is preferable that R greater than 3.0T, and more preferable that R greater than 3.5T.
In a seventh aspect of the present invention, in the mounting member of the fourth aspect, a radius of curvature at the second concave portion is smaller than the radius of curvature at the second convex portion.
A eighth aspect of the present invention is a flexible membrane dam formed by a flexible expanding-and-contracting structural body which is formed from a flexible membrane and is made to stand by a fluid being supplied to an interior thereof and made to collapse by fluid being discharged from the interior thereof; and a structure at which the flexible expanding-and-contracting structural body is provided, the flexible membrane dam having a mounting member, the mounting member being formed by a first member and a second member, wherein the first member is provided at the structure and abuts one surface of the flexible membrane, the second member abuts another surface of the flexible membrane, a vicinity of an outer peripheral edge of the flexible membrane is nipped by a fixing means between the first member and the second member, at a surface of the first member which abuts the flexible membrane, first concave portions and first convex portions, which extend in a direction orthogonal to the outer peripheral edge of the flexible membrane, are provided alternately along the outer peripheral edge of the flexible membrane, at a surface of the second member which abuts the flexible membrane, second convex portions which oppose the first concave portions and second concave portions which oppose the first convex portions are provided alternately along the outer peripheral edge of the flexible membrane, and a length L1 of the flexible membrane, in a state in which the flexible membrane is set in close contact with bottom surface of the second concave portion, from a flexible membrane outer peripheral edge side end portion of the second concave portion to an end portion of the second concave portion at a side opposite the flexible membrane outer peripheral edge side of the second concave portion, and a length L2 of the flexible membrane, in a state in which the flexible membrane is set in close contact with peak surface of the second convex portion, from a flexible membrane outer peripheral edge side end portion of the second convex portion to an end portion of the second convex portion at a side opposite the flexible membrane outer peripheral edge side of the second convex portion, are substantially equal.
In the eighth aspect, the mounting member is provided at the structure at which the flexible expanding-and-contracting structural body is provided ,at the flexible membrane dam which is set in a river or the like. More specifically, the mounting member is provided at the inclined surface portion of the structure (the mounting base).
The flexible membrane is nipped between the first member and the second member and is fixed by a fixing means (e.g., anchor bolts provided at the structure, and nuts screwed therewith, or the like).
A vicinity of the outer peripheral edge of the flexible membrane is nipped and fixed between the first member and the second member. In this way, the vicinity of the outer peripheral edge of the flexible membrane is curved in a convex and concave shape along the direction of the outer peripheral edge.
When a fluid such as air is supplied to the interior of the flexible expanding-and-contracting structural body formed from the flexible membrane so that the flexible expanding-and-contracting structural body inflates and stands, the portions of the flexible membrane at the side opposite the outer peripheral edge side stand substantially orthogonally with respect to the inclined surfaces portion. Further, due to these portions being pulled in the substantially orthogonal direction with respect to the outer peripheral edge, the flexible membrane is fit closely to the bottom surfaces of the concave portions and the peak surfaces of the convex portions of the second member.
Here, because L1 (for the second concave portion) and L2 (for the second convex portion) are set to be substantially equal, the formation of convex and concave portions in the standing portions of the flexible membrane is prevented. At the inflated flexible expanding-and-contracting structural body, stress is applied uniformly in the direction of the outer peripheral edge of the flexible membrane. Accordingly, there is no concentration of stress caused by the formation of convex and concave portions in the flexible membrane, and thus, the durability of the flexible membrane improves.
In ninth aspect of the present invention, in the flexible membrane dam of the eighth aspect, (L1/L2)xc3x97100 is substantially in a range of 80 to 120.
L1 is a length of the flexible membrane, in a state in which the flexible membrane is set in close contact with bottom surface of the second concave portion, from a flexible membrane outer peripheral edge side end portion of the second concave portion to an end portion of the second concave portion at a side opposite the flexible membrane outer peripheral edge side of the second concave portion. L2 is a length of the flexible membrane, in a state in which the flexible membrane is set in close contact with peak surface of the second convex portion, from a flexible membrane outer peripheral edge side end portion of the second convex portion to an end portion of the second convex portion at a side opposite the flexible membrane outer peripheral edge side of the second convex portion. The ratio of L1 to L2, i.e., (L1/L2)xc3x97100, falls in the range of 80 to 120. Namely, the length L2 is close to the length L1. Thus, in the flexible expanding-and-contracting structural body which is inflated, stress is applied uniformly in the direction of the outer peripheral edge of the flexible membrane.
If (L1/L2)xc3x97100 falls out of the range of 80 to 120, when the flexible expanding-and-contracting structural body inflates, there will be a local concentration of stress at the flexible membrane in a vicinity of the second member, which is not preferable.
It is preferable that (L1/L2)xc3x97100 is 85 to 115, and more preferable that (L1/L2)xc3x97100 is 95 to 105.
In a tenth aspect of the present invention, in the flexible membrane dam of the eighth or the ninth aspect, a plurality of ribs extending along the outer peripheral edge of the flexible membrane are provided at the surface of the second member which abuts the flexible membrane, and a number of ribs provided at the second convex portion is smaller than a number of ribs provided at the second concave portion.
Ribs, which extend along the outer peripheral edge of the flexible membrane, are formed at the surface of the second member which opposes the first member. In this way, the friction generated between the second member and the flexible membrane increases, and slipping at the time a large tensile force is applied to the flexible membrane can be prevented.
The number of ribs of the second convex portions is less than the number of ribs of the second concave portions. Thus, the length L2 is made to be closer to the length L1 by an amount corresponding to this number of ribs which are the difference between the number of ribs of the second convex portions and the number of ribs of the second concave portions.
In a eleventh aspect of the present invention, in any of the eighth through tenth aspects, an end portion of the second member at a side opposite a flexible membrane outer peripheral edge side of the second member includes a chamfer.
The end portion of the second member at the side opposite the flexible membrane outer peripheral edge side is a portion which abuts the flexible membrane and bendingly deforms the flexible membrane. If this end portion is sharp, the flexible membrane will bend abruptly, and the durability thereof will deteriorate. Accordingly, by subjecting this end portion to chamfering processing, the durability of the flexible membrane improves.
In a twelfth aspect of the present invention, in the flexible membrane dam of the eleventh aspect, the chamfer has a radius of curvature.
By subjecting the end portion of the second member at the side opposite the flexible membrane outer peripheral edge side to R chamfering processing, the flexible membrane curves gradually, and thus, the durability thereof is improved even more.
In a thirteenth aspect of the present invention, in the flexible membrane dam of the twelfth aspect, the flexible membrane has a thickness T, and a radius of curvature at the second convex portion is R, R greater than 2.5T.
The thickness of the flexible membrane is T, and the R chamfering processed radius of curvature at the second convex portion is R. If R greater than 2.5T, the portion abutting the flexible membrane will be a smooth circular arc.
If Rxe2x89xa62.5T, the R chamfering processed radius of curvature will be small with respect to the thickness of the flexible membrane, and the end portion will resemble a sharp configuration which is not preferable.
It is preferable that R greater than 3.0T, and more preferable that R greater than 3.5T.
In a fourteenth aspect of the present invention, in the flexible membrane dam of the twelfth aspect, a radius of curvature at the second concave portion is smaller than the radius of curvature at the second convex portion.
In a fifteen aspect of the present invention, a device for fastening a flexible membrane of an inflatable dam to a supporting structure, the device comprising: (a) a first member having a serpentine surface, and an opposing surface for placement against a supporting structure; (b) a second member having a serpentine surface corresponding to the serpentine surface of the first member, wherein when the device fastens a flexible membrane of a dam to a supporting structure, a section of the flexible member is sandwiched between the serpentine surfaces of the first and second members, with at least a portion of the serpentine surfaces nesting with one another; and (c) bolts connecting the first and second members against a supporting structure, when the device fastens a flexible membrane of an inflatable dam to a supporting structure, is provided.